2)A double slit diffraction pattern has an intensity envelop around the central

Question

2)A double slit diffraction pattern has an intensity envelop around the central maximum. And inside it there are n fringes. If the wavelength is 420nm and d=0.200 mm and a = 45 micrometers, then what is n?

3)A double slit diffraction pattern has an intensity envelopearound the central maximum. And inside it there are n fringes. If the wavelength is 420nm and d=0.200 mm and a = 45 micrometers, then what is the ratio of the intensity of the central fringe compared to the third fringe? (This should be bigger than one.)

4)Young’s Experiment is performed with wavelength 420nm and the slits are 2mm apart. How far away should you place a screen so that the closest fringes are 2mm apart?

5)You wish to coat some glass (n=1.6) with a thin film of transparent material (n=1.33) so that light of wavelength 420nm (in vacuum) does not reflect. What minimum thickness (in nm) do you need?

Explanation / Answer

1) Here, d * sin(theta) = (n + 0.5) * lambda

=>   d * sin2 = (1 + 0.5)* 420

=> d = 18051.83 nm

2)    n = (0.200 * 45 *1000 )/(420)

            =   21

3)    ratio of intensity = 9/1

4) Far away = ( 2 * 2 * 10-6)/(420 * 10-9)

                     = 9.523 m

5)    minimum thickness = (420)/(2 * 1.33)

                                        = 157.89 nm

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.